Reverse datetime (POSIXct data) axis in ggplot version 3+

Question

Trying to get Reverse datetime (POSIXct data) axis in ggplot to work under current versions (R 3.6.2, ggplot 3.2.1).

### THIS NOW WORKS ###
library(lubridate)
library(tidyverse)
library(scales)

# Some random-ish date and values to plot
n <- 3700
myData <- tibble(timestamp = now() + seq(1:n) , value = sin(seq(1:n)/100) + rnorm(n)/10)

# the 'solution' per above link
c_trans <- function(a, b, breaks = b$breaks, format = b$format) {
    a <- scales::as.trans(a)
    b <- scales::as.trans(b)

    name <- paste(a$name, b$name, sep = "-")

    trans <- function(x) a$trans(b$trans(x))
    inv <- function(x) b$inverse(a$inverse(x))

    trans_new(name, trans, inverse = inv, breaks = breaks, format=format)
}

rev_date <- c_trans("reverse", "time")

## I would like this output with the y-axis in reverse order (top to bottom) as this is a standard practise in this application.
ggplot(myData, aes(x=value, y=timestamp)) +
  geom_path() +
  scale_y_continuous( trans=rev_date)

gives error Error: Invalid input: time_trans works with objects of class POSIXct only But timestamp is of class POSIXct

myData %>% str()
Classes ‘tbl_df’, ‘tbl’ and 'data.frame':   3700 obs. of  2 variables:
 $ timestamp: POSIXct, format: "2019-12-31 10:08:00" "2019-12-31 10:08:01" "2019-12-31 10:08:02" "2019-12-31 10:08:03" ...
 $ value    : num  -0.00202 -0.06392 -0.01515 0.11406 0.16945 ...

Update: outcome as desired after loading scales library PRIOR to creating the myData df.

Answer 1

Is this what you're trying to achieve?

y-scale as time, earliest time at the bottom:

ggplot(myData, aes(y=value, x=timestamp)) +
  geom_path() +
  scale_x_datetime() + 
coord_flip()

The code posted in the question works for me. Is this the desired output: